Talk:Theory of relativity
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I think the reason for the word "relativity" should be explained on this page. What is relative, and why?
- appears to be done.
Regarding a recent change to this article--I'm no physicist, but I always thought that relativity states that mass increases as velocity approaches the speed of light. Am I wrong on this?
Rest mass is a constant, but mass itself indeed increases in such a way that one can never accelerate an object beyond c.
I'd like very much to hear about the twins paradox. Never been much comfortable with that one.
The basic non-symmetry is that one twin must accelerate to return to the other to compare ages face-to-face. Whilst they are in inertial frames, it holds. Dave McKee
Indeed, so it is not really a paradox (as is also the case for many so-called paradoxes). The twin that goes into the spaceship will be younger when arriving back, which is possible (and easy!) to describe with special relativity in the frame of the twin at Earth, but you'll need general relativity to describe correctly in the frame of the traveling twin, only to get the same result in a harder way, of course. -- JBC
It's a convention, not an absolute. In the way that mass is used currently in physics, it's an invariant between reference frames, i.e. it doesn't change with velocity. Mass = "rest mass", and "relativistic mass" is not used. There is an alternate formulation of relativity that uses the concept of "relativistic mass" because using it lets you keep using some familiar Newtonian mechanics (e.g. F=mr a). But the invariant mass approach turns out to be somewhat easier to generalise into GR, so that's what basically everyone uses now. You'll still find "relativistic mass" in some textbooks (e.g., Feynman's Lectures on Physics) and in a lot of popularisations (I think it's in "A Brief History of Time"), but not in, say, graduate level textbooks and research papers.
For more on this, see [ http://www2.corepower.com:8080/~relfaq/mass.html]. Come to think of it, this should probably be written up in mass. -- DrBob
I remember reading once upon a time in some primary school-level book on relativity that if you approached a black hole you might never experience enterring it due to time dilation -- as you approach it your velocity approaches c, but time dilation reduces subjective time to the point you never enter it. Is this true, or is this just some mangled garbage? -- SJK
That happens according to a frame of reference far from the black hole. in your frame, you are swallowed in a finite time. (from what i remember)--AN
Galileo was actually the fella who first proposed a relativity principle. I would like to (1) redo the article to review the various relativity principles or postulates. (2) Remove material that duplicates material in the Special Relativity and General Relativity entries and replace the removed stuff with links to them. (3) In short, do a more general treatment that links to more specific entries.
If there is no objection, I will replace the entry with my revision on the 16th of August, this month.
- change of mind August 20 - I think I will do a separate article on The Principle of Relativity ( new article ).
Hilbert, not Einstein ?
Some things are missing here:
The formulas of special relativity ("Lorentz transformations") where first published by Woldemar Voigt in 1887 in his paper "Über das Doppler'sche Princip". FitzGerald, Lorentz and Larmor later published the same formula's. The name "Lorentz transformation" was chosen by Poincaré, but Lorentz prefered the to call them "Relativistic transformations" because he was aware that Voigt and FitzGerald found them before him.
The theory of special relativity is not by Albert Einstein but by Jules Henri Poincaré. In 1898, Poincaré stated that simultaneity is relative. In 1902, he discusses relative space and time in "Science and hypothesis". In 1904 during his speech in Saint Louis, Poincaré stated the principle of relativity for electromagnetism (The Galileo relativity is about mechanics). On July 5th, Poincaré published his paper ""Sur la dynamique de l'électron"". This paper contains the proof that the Lorentz transformations are a group. We know for sure (from the Einstein-Solovine letters) that Einstein has read "Science & Hypothesis" in 1902. There are also good reasons to believe that Einstein has read the 1905 Poincaré paper (Einstein made summaries & translations of several physics journals for the Annalen der Physik, including the journal "Comptes rendus" in which Poincaré published.)
The theory of general relativity is not by Albert Einstein, but by David Hilbert. Hilbert sent a pre-publication of his paper to Einstein. On November 18th, 1915, Einstein writes to Hilbert to confirm he has received the article. On november 20th, Hilbert submits his paper "Die Grundlagen der Physik. (Erste Mitteilung)" - it was published in January 1916. On November 25th, Einstein submits his paper "Die Feldgleichungen der Gravitation." - it was publised before the Hilbert paper on December 2nd 1915.
In 1763, Robert Joseph Boscovich sj. anticipated the "principle of Mach", "length contraction", "time dilatation" and "invariance" in the appendix of his book "A Theory of Natural Philosophy".
In 1782, George-Louis Lesage already knew that gravity propagates at light speed.
In the 1870s, Robert Stevenson (a.k.a. "Kinertia") anticipated the principle of equivalence.
In 1872, Camille Flamarion, published the "thought experiment of Einstein" in his book "Lumen".
in 1801, Johan Georg von Soldner anticipates the effect of gravitation on light.
in 1875, S. Tolver Preston predicts atomic energy, the A-bomb and superconductivity - based on the formula E=mc²
Here are the sources (and, very convincing, I'd say) that claim Hilbert's primacy in formulation of GR:
http://www.nobel.se/physics/educational/relativity/history-1.html
http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Einstein.html
A neutral view: http://physics.rug.ac.be/Fysica/Geschiedenis/HistTopics/General_relativity.html
This one bets on Einstein, but half-heartedly: http://www.bun.kyoto-u.ac.jp/~suchii/gen.GR8.html
And this one is emotionally charged against Einstein: http://home.comcast.net/~xtxinc/einstein.htm Mir Harven 07:55, 1 Sep 2004 (UTC)
move here
Unfortunately the result was a theory that was based on circular postulates (eg. time dilation is attributable to velocity, but velocity is distance divided by time) and one which, though it is widely claimed otherwise, ultimately conflicts with empirical evidence (eg. data from GPS satellites (http://www.egtphysics.net/GPS/RelGPS.htm); Miller's (http://www.orgonelab.org/miller.htm), and Michelson-and-Gale's interferometer experiments of the early 20th Century that strongly suggest an ether; the objectively measurable, as opposed to observer-based status of so-called time dilation). It was without any reasoning that Einstein had assumed atomic oscillation to be the true measure of the flow of time, and the famous 'twin paradox' that followed from the fact that ageing is not a subjective process that depends upon reference frame, is in direct conflict with Einstein's basic postulates and reasoning, to the effect that Einsein's later general relativity must collapse also, and relativity, which is rejected by NASA and many prominent physicists, is of interest only in a historical sense. Famous anti-relatitivity papers include Guy Burniston Brown's What is Wrong With Relativity (http://homepage.ntlworld.com/academ/whatswrongwithrelativity.html); Herbert Dingle's equally critical 'Science at the Crossroads (http://russamos.narod.ru/dingle/Preface.html)' was published in 1972.
Synopsis
I agree this page should be a synopsis, in which the charcater of general principle of SR and its application inside ordinary matter should be apparent. Thus I reverted to the previous mention of these issues; please let me hear opinions.
This isn't generally accepted science.
- Special relativity thus makes a general principle with applications in physics, chemistry, and even life sciences. It not only depicts relationships between the perspectives taken from loose moving bodies. Often together with quantum mechanics, special relativity is also employed to describe microphysical motions inside lumps of condensed matter, like pebbles and biological organs such as kidneys or brain. It, e. g., was of help to electroneurobiology researchers trying to explain physiological mechanisms that enact variations of attention, and disconnection states such as sleep and coma, as electric field-mediated relativistic effects in brain biophysics (http://electroneubio.secyt.gov.ar/Effects.htm).
- Hi, Roadrunner! You had avowed, "The only thing I care to reveal about myself is that I am a subscriber to Time Warner. Roadrunner." But here you seem also revealing to hate relativity physicists, one of whose more recent sources of revenues is biophysics. You're also contributing to keep students thinking that relativity is just concerned with heavenly matters. I don't believe that a Time Warner subscriber may harbor such bad sentiments, so please remake the paragraph, if you like, but kindly put the concept back on the entry - which becomes too much impoverished otherwise. David--200.42.95.188 17:38, 15 Oct 2004 (UTC)
- While Roadrunner comes back on changing the above paragraph, I'm reverting to its previous version.
I concur for reversion of this paragraph. Even if it is scientifically founded (I take no position on this question here), it is too particular an issue for a general article about relativity. --French Tourist 14:09, 16 Oct 2004 (UTC)
- Too drastic. Since Roadrunner did not yet edit the paragraph of her/his interest, I'm pruning it into a proposed version that keeps the concept (special relativity is being growingly used in basic biomedical research) and wait for her/his opinion. Cheers.
Hi. The users trying to add here the text about the influence of the special relativity in "brain biophysics" are doing the same at es:. They provide little or no evidence apart from their own works, and answered with insults and threats when questionned. We have blocked the article and currently we are trying to decide what to do. If anyone can read Spanish, please take a look at es:Discusión:TeorÃa_de_la_Relatividad. Thanks. --es:Usuario:Dodo
I don't know whether I'm wrong on this, but I thought that the theory of relativity also states that energy and mass are interchangeable depending on the speed? Can anyone enlighten me on this subject?
- That's just a minor consequence of special relativity. The article on that has more on the subject. --Carnildo 06:43, 18 Jun 2005 (UTC)
Removed links
I've removed links to www.anti-relativity.com for the following reasons:
- The first sentence on the first page is an attack on the reader
- The first sentence in the "paradoxes" section is an attack on the reader's intelligence. Further, the author demonstrates that he doesn't understand either the twin paradox or the doppler effect with respect to light.
- The author confuses zero-point energy with aether.
- The forum only has three threads and four posts.
--Carnildo 17:52, 5 Apr 2005 (UTC)